1. Field of the Invention
The present invention relates to a folding cellular phone, particularly to a folding cellular phone in which a liquid crystal display part is supported to be changeable between landscape and portrait orientation.
2. Description of Related Art
In recent years, cellular phones are provided with various capabilities in addition to the communication function, such as e-mail transmission/reception, digital camera shooting, recording/reproducing, television reception, scheduling and so on.
However, the chief function of the cellular phone is making and receiving calls. For greater portability and salability of the cellular phone, importance has been placed on downsizing and weight reduction. In view of operability, the cellular phone is vertically oriented and reduced in width.
When a liquid crystal display part of the cellular phone is fixed in the portrait orientation, a landscape image needs to be scaled down so that the image fits in the portrait screen or a viewer has to scroll the image horizontally to see the whole image.
If rotated 90 degrees, the landscape image is displayed full on the portrait display without scaling down. The liquid crystal display part and an operation part of the folding cellular phone come into sight when the cellular phone is opened. When the user rotates the cellular phone 90 degrees to see the landscape image, the operation part is also rotated 90 degrees. It is troublesome and difficult for the user to do input with the operation keys in such an unusual orientation.
To solve the problem, for example, Japanese Unexamined Patent Publication No. 2001-156893 discloses a folding cellular phone including a liquid crystal display part which is supported on a first housing such that the orientation thereof is changeable from portrait to landscape while the cellular phone itself is held in the portrait orientation. The liquid crystal display part of the folding cellular phone is supported by a rotation axis arranged at a center portion thereof to extend vertical to the liquid crystal display part such that the liquid crystal display part is rotated 90 degrees about the rotation axis.
In order to rotate the liquid crystal display part without contacting a second housing so as not to cause damage to the liquid crystal display part and the second housing while preventing an increase in size and thickness of the cellular phone, the bottom side of the liquid crystal display part needs to be rounded to form an arc corresponding to the circumference of a circle having the rotation axis as the center, or alternatively, the rotation axis is positioned away from the second housing. In such a case, the liquid crystal display part cannot be enlarged or the size of the cellular phone itself increases.
For example, Japanese Unexamined Patent Publication No. 2003-319043 discloses a folding cellular phone including a support mechanism for supporting the liquid crystal display part on a first housing in a slidable and rotatable manner. The liquid crystal display part of the folding cellular phone first slides in the vertical direction and then rotates about a rotation axis arranged at a center portion of the liquid crystal display part. Therefore, the liquid crystal display part does not contact the second housing and the liquid crystal display part and the second housing are not damaged. Thus, the liquid crystal display part is enlarged.
Further, Japanese Unexamined Patent Publication No. 2004-78073 discloses a support mechanism for a liquid crystal display device which makes it possible to change the orientation of the liquid crystal display part between portrait and landscape.
In the near future, digital terrestrial television broadcasting will begin in earnest. Unlike the conventional analog television broadcasting, the digital terrestrial television broadcasting provides so-called interactive services. For example, people can take part in a quiz show, do shopping or complete payment to a bank account through a television set.
If the cellular phone is configured to receive the digital terrestrial television broadcasting, the user needs to operate the keys looking at an image on the display screen. In general, television images are landscape-oriented. Therefore, in order to see the landscape television image as large as possible on the small liquid crystal display of the cellular phone, the liquid crystal display needs to be landscape-oriented.
The cellular phone according to Japanese Unexamined Patent Publication No. 2003-319043, however, requires two kinds of movements, i.e., slide and rotation, to change the orientation. These movements cannot be achieved by a single hand, thereby complicating the operation.
Further, the liquid crystal display device according to Japanese Unexamined Patent Publication No. 2004-78073 is not required to reduce the size and weight as strictly as the cellular phone is. In addition, the liquid crystal display part thereof does not require frequent changes between portrait and landscape orientation. Therefore, the switching mechanism is complicated and the operation thereof is also complicated.